1. Field of the Invention
The present invention relates to a thermoplastic resin composition which gives a molded article having improved balance among heat resistance, chemical resistance, impact resistance and a shrinkage factor; falling ball impact resistance; weld strength; and appearance.
2. Description of the Related Art
Polycarbonate resins have good heat resistance and impact strength and are used in many technical fields such as vehicles. However the polycarbonate resins have unsatisfactory chemical resistance and large dependency of the impact strength on a thickness of a molded article.
To improve the chemical resistance of the polycarbonate resin, it is proposed to blend the polycarbonate resin with a saturated polyester a typical example of which is polybutylene terephthalate. However, such blend deteriorates impact strength which is one of the characteristics of the polycarbonate resin and has an unsatisfactory shrinkage factor. In addition, the blend cannot improve the dependency of impact strength on the thickness.
Recently, various ternary resin compositions comprising a polycarbonate resin, a saturated polyester and a rubber or a copolymer. However, the ternary compositions do not have good balance among heat resistance, chemical resistance, impact strength and a shrinkage factor. In addition, since the ternary compositions comprises plural components, a molded article of the compositions has poor falling ball impact strength and weld strength.